Ionic displacements and piezoelectric constants of AgGaS[sub 2] from x-ray diffraction of a crystal in an external electric field

Journal Article · Sun Aug 01 00:00:00 EDT 1993 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1006/jssc.1993.1244· OSTI ID:7207446

Graafsma, H; Coppens, P ^[1]; Majewski, J; Cahen, D ^[2]

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1. State Univ. of New York, Buffalo, NY (United States)
2. Weizmann Institute of Science, Rehovot (Israel)

The displacements of the ions and the changes in cell parameters which occur on application of an electric field to a crystal of AgGaS[sub 2] have been determined using X-ray diffraction. The shifts in Bragg angle of 14 reflections, due to a field of 2.6 X 10[sup 6] V/m applied nearly parallel to [221], were used to refine the change in cell parameters. The resulting piezoelectric coefficients are d[sub 14] = d[sub 25] = 8.8 (0.9) x 10[sup [minus]12] C/N and d[sub 36] = 7.6 (1.8) x 10[sup [minus]12] C/N. This leads to a value of 4.8 (0.5) x 10[sup [minus]12] pC/N for the piezoelectric constant in the [221] direction, which compares well with a value of 5-6 x 10[sup [minus]12] C/N measured directly. The ionic displacements were studied for two field directions. With E = 2.6 x 10[sup 6] V/m in a direction parallel to [110], very small, but significant a and b direction displacements were observed for all atoms, whereas the displacements in the c direction were negligible as expected. Relative to the sulfur framework, the Ga ion displacement is considerably larger than that of the Ag ions. The changes in scattering intensity for a field direction. The ion displacements are analyzed with a model of nonpolarizable harmonic oscillators in an electric field. It is found that the observed displacements of the Ga ions are much larger than the calculated displacements, whereas the displacements of the Ag ion are in good agreement with theory.

• OSTI ID: 7207446
• Journal Information: Journal of Solid State Chemistry; (United States), Vol. 105:2; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
GALLIUM SULFIDES
CRYSTAL STRUCTURE
SILVER SULFIDES
ELECTRIC FIELDS
LATTICE PARAMETERS
MATHEMATICAL MODELS
CHALCOGENIDES
GALLIUM COMPOUNDS
SILVER COMPOUNDS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360602* - Other Materials- Structure & Phase Studies
360604 - Materials- Corrosion
Erosion
& Degradation